JP6266364B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to a control device for an internal combustion engine provided with a variable valve timing mechanism that changes a rotational phase of a camshaft relative to a crankshaft by adjusting a rotational speed of a motor.

Patent Document 1 discloses a variable valve that changes the valve timing by changing the rotational phase of the camshaft relative to the crankshaft by adjusting the rotational speed of the motor with respect to the rotational speed that is ½ of the rotational speed of the crankshaft. A control device for a timing device is disclosed.
In this control device, every time the cam angle signal is output from the cam angle sensor, the actual valve timing is calculated based on the cam angle signal and the crank angle signal output from the crank angle sensor. The valve timing change amount is calculated based on the difference between the rotation speed of the motor and the half of the rotation speed of the crankshaft in the calculation cycle, and based on the calculated value of the actual valve timing and the calculated value of the valve timing change amount. Thus, the final actual valve timing is calculated.

Japanese Patent No. 4123127

  By the way, if the sensor used to detect the rotational phase of the camshaft relative to the crankshaft fails during the rotational phase change (transient state of the variable valve timing mechanism) and the detection of the rotational phase is stopped, Even if an operation to stop the change of the rotation phase with the stop of the detection of the rotation phase is performed, the rotation phase changes due to the inertia of the variable valve timing mechanism, and the actual rotation phase overruns the target according to the operating state. There was a possibility of becoming an angle or an over-delayed state.

  An engine in which the actual rotational phase is excessively advanced or retarded from the target causes a collision with a stopper that regulates the variable range of the rotational phase, or the valve timing is changed by a variable valve timing mechanism. When there is interference between the valve (intake valve or exhaust valve) and the piston, or when the valve timing of the intake valve is made variable, the intake valve is closed after the bottom dead center to delay the intake air amount. May cause engine stall.

  The present invention has been made in view of the above problems, and an object of the present invention is to continue detection of a rotational phase even if a part of a sensor for detecting the rotational phase of a camshaft with respect to a crankshaft fails. And

According to the present invention, in one aspect thereof, the larger one of the rotation amount of the cam sprocket calculated based on the crank angle signal and the rotation amount of the cam sprocket calculated based on the cam angle signal is selected, and the selected cam The amount of change in the rotational phase is obtained from the amount of rotation of the sprocket and the amount of rotation of the motor shaft calculated based on the output of the motor rotation angle sensor.

According to the above invention, when an abnormality occurs in one of the crank angle sensor and the cam angle sensor, the rotational phase is erroneously detected on the retard side than the actual, and the valve timing is over-advanced from the target. Can be suppressed.

1 is a system configuration diagram of an internal combustion engine in an embodiment of the present invention. It is sectional drawing which shows the variable valve timing mechanism in embodiment of this invention. It is sectional drawing which shows the variable valve timing mechanism in embodiment of this invention, Comprising: It is the sectional view on the AA line of FIG. It is sectional drawing which shows the variable valve timing mechanism in embodiment of this invention, Comprising: It is the BB sectional drawing of FIG. It is a functional block diagram which shows the detail of the detection process of rotational phase and rotational phase control in embodiment of this invention. It is a functional block diagram which shows another example of the selection output process of angle variation | change_quantity (DELTA) ASP in embodiment of this invention. It is a figure which shows the output characteristic of the output switching part in the functional block diagram of FIG. It is a functional block diagram which shows the calculation process of angle variation | change_quantity (DELTA) ASP1 using the exhaust side cam angle sensor in embodiment of this invention. It is a functional block diagram which shows the calculation process of angle variation | change_quantity (DELTA) ASP1 using the count value of the output signal of the cam angle sensor in embodiment of this invention. It is a functional block diagram which shows the calculation process of angle variation | change_quantity (DELTA) ASP2 based on the output period of the crank angle sensor in embodiment of this invention. It is a functional block diagram which shows another example of the rotation phase detection process and rotation phase control in embodiment of this invention. It is a time chart for demonstrating the default control based on the failure diagnosis in embodiment of this invention, and the clear process of an integrated value.

Embodiments of the present invention will be described below.
FIG. 1 is a diagram showing an example of an internal combustion engine to which a control device according to the present invention is applied.
The internal combustion engine 101 is mounted on a vehicle and used as a power source.

The intake duct 102 of the internal combustion engine 101 is provided with an intake air amount sensor 103 that detects the intake air flow rate QA of the internal combustion engine 101.
The intake valve 105 opens and closes the intake port of the combustion chamber 104 of each cylinder.

A fuel injection valve 106 is arranged for each cylinder in the intake port 102 a on the upstream side of the intake valve 105.
The internal combustion engine 101 shown in FIG. 1 is a so-called port injection type internal combustion engine in which the fuel injection valve 106 injects fuel into the intake port 102 a, but the fuel injection valve 106 injects fuel directly into the combustion chamber 104. The so-called in-cylinder direct injection internal combustion engine can be obtained.

The fuel injected from the fuel injection valve 106 is sucked together with air into the combustion chamber 104 via the intake valve 105 and ignited and burned by spark ignition by the spark plug 107, and the pressure by the combustion causes the piston 108 to be applied to the crankshaft 109. By pushing down, the crankshaft 109 is rotationally driven.
Further, the exhaust valve 110 opens and closes the exhaust port of the combustion chamber 104, and the exhaust valve 110 is opened so that the exhaust gas in the combustion chamber 104 is discharged to the exhaust pipe 111.

A catalytic converter 112 having a three-way catalyst or the like is installed in the exhaust pipe 111, and exhaust gas is purified by the catalytic converter 112.
The intake valve 105 opens with the rotation of the intake camshaft 115a that is rotationally driven by the crankshaft 109. Further, the exhaust valve 110 opens with the rotation of the exhaust camshaft 115 b that is driven to rotate by the crankshaft 109.

The variable valve timing mechanism 114 changes the relative rotational phase angle of the intake camshaft 115a with respect to the crankshaft 109 by a motor (electric motor) as an actuator, so that the phase of the valve operating angle of the intake valve 105, that is, the intake valve 105 This is an electric variable valve timing mechanism that continuously changes the valve timing (open timing IVO and close timing IVC of the intake valve 105) in the advance angle direction and the retard angle direction.
An ignition module 116 that supplies ignition energy to the ignition plug 107 is directly attached to the ignition plug 107 provided for each cylinder. The ignition module 116 includes an ignition coil and a power transistor that controls energization of the ignition coil.

  A control device (electronic control unit) 201 including a microcomputer inputs signals from various sensors and switches, and performs arithmetic processing according to a program stored in a memory in advance, so that the fuel injection valve 106, variable valve timing, and so on. The operation amounts of various devices such as the mechanism 114 and the ignition module 116 are calculated and output.

  The control device 201 receives the output signal of the intake air amount sensor 103, detects the crank angle sensor 203 that outputs the rotation angle signal POS of the crankshaft 109, and the depression amount of the accelerator pedal 207, in other words, the accelerator opening degree ACC. An accelerator opening sensor 206 that performs the operation, a cam angle sensor 204 that outputs a rotation angle signal CAM of the intake camshaft 115a, a water temperature sensor 208 that detects a temperature TW of the cooling water of the internal combustion engine 101, and an exhaust pipe 111 upstream of the catalytic converter 112. The air-fuel ratio sensor 209 detects the air-fuel ratio AF based on the oxygen concentration in the exhaust, and detects the rotation angle (magnetic pole position) of the motor (motor 12 in FIG. 2) that is the actuator of the variable valve timing mechanism 114. An output signal from the motor rotation angle sensor 210 or the like is input, and the internal combustion engine 101 is further input. Ignition switch is a main switch of the operation and stop inputs a signal (engine switch) 205.

The rotation angle signal POS output from the crank angle sensor 203 is a pulse signal for each unit crank angle (for example, 10 deg CA), and corresponds to a stroke phase difference (ignition interval) between cylinders (crank in a four-cylinder engine). It is configured such that one or a plurality of pulses are lost every 180 deg).
The crank angle sensor 203 outputs a rotation angle signal POS (unit crank angle signal) for each unit crank angle and a reference crank angle signal for each crank angle corresponding to the stroke phase difference (ignition interval) between the cylinders. It can be configured as follows. Here, the missing position of the rotation signal POS for each unit crank angle or the output position of the reference crank angle signal represents the reference piston position of each cylinder.

The cam angle sensor 204 outputs a rotation angle signal CAM for each crank angle corresponding to the stroke phase difference (ignition interval) between the cylinders.
Here, since the intake camshaft 115a rotates at half the rotational speed of the crankshaft 109, the internal combustion engine 101 is a four-cylinder engine, and the crank angle corresponding to the stroke phase difference (ignition interval) between the cylinders is 180 degCA. If so, the crank angle 180 deg CA corresponds to the rotation angle 90 deg of the intake camshaft 115 a. That is, the cam angle sensor 204 outputs a cylinder discrimination signal (rotation signal CAM) every time the intake camshaft 115a rotates 90 degrees.

The rotation angle signal CAM is a signal (cylinder discrimination signal) for discriminating the cylinder located at the reference piston position, and represents the cylinder number for each crank angle corresponding to the stroke phase difference (ignition interval) between the cylinders. Output as a characteristic pulse.
For example, in the case of a four-cylinder engine and the ignition order is the first cylinder, the third cylinder, the fourth cylinder, and the second cylinder, the cam angle sensor 204 has one pulse signal for each crank angle of 180 deg, By outputting the pulse signal, the four pulse signals, and the two pulse signals, the cylinder located at the reference piston position can be specified based on the number of pulses. Further, the rotation angle signal CAM can represent the cylinder number based on the pulse width and amplitude instead of representing the cylinder number by the number of pulses.

2 to 4 show an example of the structure of the variable valve timing mechanism 114.
The structure of the variable valve timing mechanism 114 is not limited to that illustrated in FIGS. 2 to 4, and a known variable valve that changes the rotational phase of the camshaft relative to the crankshaft by adjusting the rotational speed of the motor. A timing mechanism can be appropriately employed.

  The variable valve timing mechanism 114 is rotatably supported on a timing sprocket (cam sprocket) 1 which is a driving rotary body rotated by a crankshaft 109 of the internal combustion engine 101 and a cylinder head via a bearing 44. The intake camshaft 115a that rotates by the rotational force transmitted from 1, the cover member 3 that is disposed at the front position of the timing sprocket 1 and is fixed to the chain cover 40 by bolts, and the timing sprocket 1 and the intake camshaft 115a. And a phase changing mechanism 4 that is disposed between the timing sprocket 1 and changes the relative rotational phase angle of the intake camshaft 115a.

The timing sprocket 1 includes a sprocket body 1a and a gear portion 1b that is integrally provided on the outer periphery of the sprocket body 1a and receives a rotational force from the crankshaft 109 via a wound timing chain 42. .
In addition, the timing sprocket 1 is interposed between a circular groove 1c formed on the inner peripheral side of the sprocket body 1a and an outer periphery of a flange portion 2a provided integrally with the front end portion of the intake camshaft 115a. A ball bearing 43 rotatably supports the intake camshaft 115a.

An annular protrusion 1e is integrally formed on the outer peripheral edge of the front end portion of the sprocket body 1a.
At the front end portion of the sprocket body 1a, an annular member 19 that is coaxially positioned on the inner peripheral side of the annular protrusion 1e and has inner teeth 19a that are wavy engagement portions formed on the inner periphery, an annular plate 6 and Are fastened together by bolts 7 from the axial direction.

Further, as shown in FIG. 4, a stopper convex portion 1d, which is an arcuate engaging portion, is formed on a part of the inner peripheral surface of the sprocket body 1a up to a predetermined length range along the circumferential direction.
A cylindrical housing 5 protruding forward in a state of covering each component of a speed reducer 8 and an electric motor 12 described later of the phase changing mechanism 4 is fixed to the outer periphery of the front end side of the plate 6 by bolts 11.

The housing 5 is made of an iron-based metal and functions as a yoke. The housing 5 integrally has an annular plate-shaped holding portion 5a on the front end side, and the entire outer peripheral side including the holding portion 5a is covered by the cover member 3. It is arranged in a form covered with a predetermined gap.
The intake camshaft 115 a has a drive cam (not shown) that opens the intake valve 105 on the outer periphery, and a driven member 9 that is a driven rotating body at the front end portion is coupled from the axial direction by a cam bolt 10.

Further, as shown in FIG. 4, a stopper concave groove 2b, which is a locking portion into which the stopper convex portion 1d of the sprocket body 1a is engaged, is formed in the flange portion 2a of the intake camshaft 115a along the circumferential direction. ing.
The stopper concave groove 2b is formed in a circular arc shape having a predetermined length in the circumferential direction, and both end edges of the stopper convex portion 1d rotated in this length range are in contact with the opposing edges 2c and 2d in the circumferential direction, respectively. Thus, the relative rotational position of the intake camshaft 115a relative to the timing sprocket 1 on the maximum advance angle side and the maximum retard angle side is regulated.

That is, the angular range in which the stopper convex portion 1d can move within the stopper concave groove 2b is a variable range of the relative rotational phase angle of the intake camshaft 115a with respect to the crankshaft 109, in other words, a variable range of valve timing.
A flange-shaped seating surface portion 10c is integrally formed on an end edge of the head portion 10a of the cam bolt 10 on the shaft portion 10b side, and is formed on the outer periphery of the shaft portion 10b from the end portion of the intake camshaft 115a to the inner axial direction. A male screw portion that is screwed onto the female screw portion is formed.

The driven member 9 is formed of an iron-based metal material and, as shown in FIG. 3, includes a disc portion 9a formed on the front end side and a cylindrical cylindrical portion 9b formed integrally on the rear end side. Has been.
An annular step protrusion 9c having substantially the same outer diameter as that of the flange portion 2a of the intake camshaft 115a is integrally provided on the disc portion 9a at a substantially central position in the radial direction of the rear end surface.

The outer peripheral surface of the step protrusion 9 c and the outer peripheral surface of the flange portion 2 a are inserted and arranged in the inner periphery of the inner ring 43 a of the third ball bearing 43. The outer ring 43b of the third ball bearing 43 is press-fitted and fixed to the inner peripheral surface of the circular groove 1c of the sprocket body 1a.
A retainer 41 for holding a plurality of rollers 34 is integrally provided on the outer peripheral portion of the disc portion 9a.

The retainer 41 is formed to protrude from the outer peripheral portion of the disc portion 9a in the same direction as the cylindrical portion 9b, and is formed by a plurality of elongated protrusion portions 41a having predetermined gaps at substantially equal intervals in the circumferential direction. ing.
The cylindrical portion 9b is formed with a through hole 9d through which the shaft portion 10b of the cam bolt 10 is inserted in the center, and a first needle bearing 30 is provided on the outer peripheral side of the cylindrical portion 9b.

The cover member 3 is formed of a synthetic resin material, and includes a cover body 3a that swells in a cup shape, and a bracket 3b that is integrally provided on the outer periphery of the rear end of the cover body 3a.
The cover body 3a is arranged so as to cover the entire front end side of the phase changing mechanism 4, that is, substantially the entire rear end side from the holding portion 5b in the axial direction of the housing 5 with a predetermined gap. On the other hand, the bracket 3b is formed in a substantially annular shape, and bolt insertion holes 3f are formed through the six boss portions.

Further, the bracket 3b is fixed to the chain cover 40 via a plurality of bolts 47 on the cover member 3, and inner and outer double slip rings 48a and 48b are provided on the inner peripheral surface of the front end 3c of the cover body 3a. It is buried and fixed with the end face exposed.
Furthermore, the upper end portion of the cover member 3 is provided with a connector portion 49 in which connector terminals 49a connected to slip rings 48a and 48b via conductive members are fixed.

The connector terminal 49a is supplied with power from a battery power source (not shown) via the control device 201.
A large-diameter first oil seal 50 as a seal member is interposed between the inner peripheral surface on the rear end side of the cover body 3a and the outer peripheral surface of the housing 5.

The first oil seal 50 is formed in a substantially U-shaped cross section, a core metal is embedded inside the synthetic rubber base material, and the annular base 50a on the outer peripheral side is the inner end of the cover member 3a. It is fitted and fixed in a circular groove 3d formed on the peripheral surface.
Further, a seal surface 50 b that contacts the outer peripheral surface of the housing 5 is integrally formed on the inner peripheral side of the annular base portion 50 a of the first oil seal 50.

The phase changing mechanism 4 includes a motor 12 disposed on the substantially coaxial front end side of the intake camshaft 115a, and a speed reducer 8 that reduces the rotational speed of the motor 12 and transmits it to the intake camshaft 115a. .
The motor 12 is, for example, a DC motor with a brush, and includes a housing 5 that is a yoke that rotates integrally with the timing sprocket 1, a motor shaft 13 that is an output shaft rotatably provided inside the housing 5, and a housing 5 is provided with a pair of semicircular arc permanent magnets 14 and 15 fixed to the inner peripheral surface of 5 and a stator 16 fixed to the inner bottom surface side of the housing holding portion 5a.

The motor shaft 13 is formed in a cylindrical shape and functions as an armature. An iron core rotor 17 having a plurality of poles is fixed to the outer periphery at a substantially central position in the axial direction, and an electromagnetic coil 18 is disposed on the outer periphery of the iron core rotor 17. It is wound.
A commutator 20 is press-fitted and fixed to the outer periphery of the front end portion of the motor shaft 13, and the commutator 20 is connected to an electromagnetic coil 18 in each segment divided into the same number as the number of poles of the iron core rotor 17.

The motor shaft 13 includes a needle bearing 28 that is a first bearing and a fourth ball that is a bearing that is disposed on the side of the needle bearing 28 in the axial direction on the outer peripheral surface of the shaft portion 10 b on the head 10 a side of the cam bolt 10. A bearing 35 is rotatably supported.
A cylindrical eccentric shaft portion 30 constituting a part of the speed reducer 8 is integrally provided at the rear end portion of the motor shaft 13 on the intake camshaft 115a side.

Further, a second oil seal 32 that is a friction member that prevents leakage of lubricating oil from the inside of the reduction gear 8 into the motor 12 is provided between the outer peripheral surface of the motor shaft 13 and the inner peripheral surface of the plate 6. ing.
The second oil seal 32 imparts frictional resistance against the rotation of the motor shaft 13 by the inner peripheral portion elastically contacting the outer peripheral surface of the motor shaft 13.

The speed reducer 8 includes an eccentric shaft portion 30 that performs eccentric rotational motion, a second ball bearing 33 that is a second bearing provided on the outer periphery of the eccentric shaft portion 30, and a roller provided on the outer periphery of the second ball bearing 33. 34, a holder 41 that allows the roller 34 to move in the rolling direction while holding the roller 34 in the rolling direction, and a driven member 9 that is integral with the holder 41.
The axis of the cam surface formed on the outer peripheral surface of the eccentric shaft portion 30 is slightly eccentric in the radial direction from the axis X of the motor shaft 13. The second ball bearing 33 and the roller 34 are configured as a planetary meshing portion.

The second ball bearing 33 is formed in a large diameter, and is disposed so as to be substantially overlapped at the radial position of the first needle bearing 28, and the inner ring 33 a of the second ball bearing 33 is disposed on the eccentric shaft portion 30. While being press-fitted and fixed to the outer peripheral surface, the roller 34 is always in contact with the outer peripheral surface of the outer ring 33 b of the second ball bearing 33.
Further, an annular gap C is formed on the outer peripheral side of the outer ring 33, and the entire second ball bearing 33 can be moved in the radial direction along with the eccentric rotation of the eccentric shaft portion 30, that is, eccentrically movable. It has become.

Each roller 34 is fitted in the internal teeth 19a of the annular member 19 while moving in the radial direction along with the eccentric movement of the second ball bearing 33, and is guided in the circumferential direction by the protrusion 41a of the cage 41 in the radial direction. Is designed to swing.
Lubricating oil is supplied into the reduction gear 8 by lubricating oil supply means.

  The lubricating oil supply means is formed in the cylinder head bearing 44 and is formed in the direction of the internal axis of the intake camshaft 115a and the oil supply passage 44a through which the lubricating oil is supplied from the main oil gallery (not shown). An oil supply hole 48 communicated with the passage 44a via a groove groove, and is formed so as to penetrate the driven member 9 in the inner axial direction, with one end opening to the oil supply hole 48 and the other end being a first needle bearing 28 and a second ball bearing. The small oil supply hole 45 opened in the vicinity of 33 and three large oil discharge holes (not shown) that are also formed through the driven member 9 are formed.

Hereinafter, the operation of the variable valve timing mechanism 114 will be described.
First, when the crankshaft 109 of the internal combustion engine 101 is rotationally driven, the timing sprocket 1 is rotated via the timing chain 42, and the motor 12 is synchronously rotated via the housing 5, the annular member 19 and the plate 6 by the rotational force.

On the other hand, the rotational force of the annular member 19 is transmitted from the roller 34 to the intake camshaft 115a via the retainer 41 and the driven member 9. As a result, the cam of the intake camshaft 115a opens and closes the intake valve 105.
The control device 201 energizes the electromagnetic coil 17 of the motor 12 when changing the relative rotational phase angle of the intake camshaft 115a with respect to the crankshaft 109, that is, the valve timing of the intake valve 105, by the variable valve timing mechanism 114. Then, the motor 12 is driven. When the motor 12 is driven to rotate, this motor rotational force is transmitted to the intake camshaft 115a via the speed reducer 8.

That is, when the eccentric shaft portion 30 rotates eccentrically with the rotation of the motor shaft 13, each roller 34 is guided by one of the annular members 19 while being radially guided by the protrusion 41 a of the retainer 41 for each rotation of the motor shaft 13. The robot moves over the inner teeth 19a while rolling to other adjacent inner teeth 19a, and repeats this in order to make rolling contact in the circumferential direction.
The rotational force is transmitted to the driven member 9 while the rotation of the motor shaft 13 is decelerated by the rolling contact of the rollers 34. The reduction ratio when the rotation of the motor shaft 13 is transmitted to the driven member 9 can be arbitrarily set depending on the number of rollers 34 and the like.

As a result, the intake camshaft 115a rotates forward and backward relative to the timing sprocket 1 to convert the relative rotational phase angle, and the opening / closing timing of the intake valve 105 is changed to the advance side or the retard side.
Here, the forward / reverse relative rotation of the intake camshaft 115a with respect to the timing sprocket 1 is restricted by each side surface of the stopper convex portion 1d coming into contact with one of the opposing surfaces 2c and 2d of the stopper concave groove 2b.

  That is, the driven member 9 rotates in the same direction as the rotation direction of the timing sprocket 1 as the eccentric shaft portion 30 rotates eccentrically, so that one side surface of the stopper convex portion 1d is opposed to one side of the stopper groove 2b. A further rotation in the same direction is restricted by contacting the surface 1c. As a result, the intake camshaft 115a has its relative rotational phase angle with respect to the timing sprocket 1 changed to the maximum advance side.

On the other hand, when the driven member 9 rotates in the direction opposite to the rotation direction of the timing sprocket 1, the other side surface of the stopper convex portion 1d abuts against the opposite surface 2d on the other side of the stopper concave groove 2b and further in the same direction. Rotation is regulated. Thereby, the relative rotation phase of the intake camshaft 115a with respect to the timing sprocket 1 is changed to the maximum on the retard side.
As described above, the control device 201 controls the energization of the motor 12 of the variable valve timing mechanism 114 to variably control the relative rotational phase angle of the intake camshaft 115a with respect to the crankshaft 109, that is, the valve timing of the intake valve 105. To do.

The control device 201 determines the target phase angle TA (in other words, the target advance angle amount, the target valve timing, the target conversion) based on the operating state of the internal combustion engine 101, for example, the engine load, the engine speed, the engine temperature, the starting state, and the like. While calculating the angle, the actual relative rotational phase angle RA of the intake camshaft 115a with respect to the crankshaft 109 is detected.
Then, the control device 201 performs feedback control of the rotational phase, which calculates and outputs the operation amount of the electric motor 12 so that the actual relative rotational phase angle RA approaches the target phase angle TA. In the feedback control, the control device 201 calculates the operation amount of the electric motor 12 by, for example, proportional-integral control based on a deviation between the target phase angle TA and the actual relative rotational phase angle RA.

The control device 201 detects the actual relative rotational phase angle RA based on the outputs of the crank angle sensor 203, the cam angle sensor 204, and the motor rotational angle sensor 210 as shown in the functional block diagram of FIG.
The rotation phase calculation unit 501 receives the rotation angle signal POS output from the crank angle sensor 203 and the rotation angle signal CAM output from the cam angle sensor 204.

The rotation phase calculation unit 501 performs an interruption process every time the rotation angle signal CAM is input (every crank angle corresponding to the stroke phase difference (ignition interval) between cylinders), and the rotation angle signal CAM and the rotation angle signal POS. Based on the above, the actual relative rotational phase angle RA1 (degCA) is calculated.
In the present embodiment, the angle unit degCA represents the angle of the crankshaft 109.

For example, the rotation phase calculation unit 501 determines the angle from the reference crank angle position detected based on the rotation angle signal POS to the input of the rotation angle signal CAM based on the count value of the rotation angle signal POS and the engine rotation speed. The actual relative rotational phase angle RA1 of the intake camshaft 115a with respect to the crankshaft 109 is calculated by measuring by time angle conversion or the like.
Therefore, the actual relative rotational phase angle RA1 detected by the rotational phase calculation unit 501 is every time the rotational angle signal CAM is inputted, in other words, every crank angle corresponding to the stroke phase difference (ignition interval) between the cylinders. The previous detection value is held until the rotation angle signal CAM is next input after the update.

Note that the actual relative rotational phase angle RA1 represents the advanced crank angle (degCA) from the most retarded position (initial position, default position) of the valve timing of the intake valve 105. Therefore, when the valve timing of the intake valve 105 is the most retarded position, the actual relative rotation phase angle RA1 = 0 degCA, and the actual relative rotation phase angle RA1 becomes larger as the valve timing of the intake valve 105 is advanced. Will be calculated.
Further, when the rotation angle signal CAM represents the cylinder number based on the number of pulses output as a group, the rotation phase calculation unit 501 performs an actual relative rotation phase angle by an interrupt process based on the leading pulse signal of the group of pulse signals. It is assumed that RA1 calculation processing is performed.

The CAM cycle calculation unit 502 measures a CAM cycle TREF (ms), which is a generation cycle of the rotation angle signal CAM, by interruption processing based on the input of the rotation angle signal CAM output from the cam angle sensor 204. That is, the difference between the timer value (free run counter value) at the time of the previous interrupt processing and the timer value at the time of the current interrupt processing execution is calculated as the rotation angle signal CAM generation cycle TREF (ms). .
When the internal combustion engine 101 is a four-cylinder engine and the stroke phase difference (ignition interval) between the cylinders is 180 degCA in terms of crank angle, the CAM cycle calculation unit 502 is the time required for the crankshaft 109 to rotate by 180 degCA, in other words, For example, the time required for the sprocket 1 to rotate by 90 degrees is measured.

The POS count unit 503 updates the count value NPOS of the rotation angle signal POS by interruption processing every time the rotation angle signal POS output from the crank angle sensor 203 is input. That is, every time the rotation angle signal POS is input, the POS count unit 503 increases the count value NPOS up to the previous time by a predetermined value.
The rotation amount calculation unit 504 reads the latest CAM cycle TREF calculated by the CAM cycle calculation unit 502 by interruption processing every predetermined time Δt, and changes the angle of the sprocket 1 per predetermined time Δt from the read CAM cycle TREF. The amount ΔASP1 (deg), in other words, the amount of rotation (rotational speed) per predetermined time Δt (unit time) of the sprocket 1 is calculated. The predetermined time Δt can be set to 1 ms, for example.

Since the CAM cycle TREF (ms) is the time required for the sprocket 1 to rotate by 90 deg as described above, the angle change amount (rotation amount) of the sprocket 1 per 1 ms is “90 deg / CAM cycle TREF (ms)”. When the predetermined time Δt = 1 ms, “angle change amount ΔASP1 (deg) = 90 deg / CAM cycle TREF (ms)”.
The count change amount calculation unit 505 reads the count value NPOS updated by the POS count unit 503 in an interrupt process every predetermined time Δt, and reads the count value NPOS read last time (before the predetermined time Δt) and the count value read this time. The difference from NPOS is calculated as the change amount ΔNPOS of the count value NPOS per predetermined time Δt.

  Each time the count change amount calculation unit 505 calculates the change amount ΔNPOS, the unit conversion unit 506 converts the change amount ΔNPOS into the crank angle change amount ΔCA per predetermined time Δt based on the angular period (degCA) of the rotation signal POS. Convert to (degCA). That is, the unit converter 506 sets “change amount ΔNPOS” × “angle period (degCA) of the rotation signal POS” to the crank angle change amount ΔCA (degCA) per predetermined time Δt, in other words, per predetermined time Δt. Calculated as the amount of rotation of the crankshaft 109.

The multiplication unit 507 multiplies the crank angle change amount ΔCA (degCA) by 1/2 each time the unit conversion unit 506 calculates the crank angle change amount ΔCA (degCA), so that the sprocket 1 per predetermined time Δt. Angle change amount ΔASP2 (deg), in other words, the amount of rotation of the sprocket 1 per predetermined time Δt.
Since the rotation speed of the sprocket 1 is half of the rotation speed of the crankshaft 109, when the rotation angle of the crankshaft 109 changes by ΔCA (degCA) per predetermined time Δt, the rotation angle of the sprocket 1 is ΔCA / 2 ( deg).

The angle change amount ΔASP1 (deg) calculated by the rotation amount calculation unit 504 and the angle change amount ΔASP2 (deg) calculated by the multiplication unit 507 are input to the selection unit (select high processing unit) 508.
The selection unit 508 selects the larger one of the angle change amount ΔASP1 (deg) and the angle change amount ΔASP2 (deg), in other words, the sprocket 1 per predetermined time Δt obtained based on the rotation signal CAM output from the cam angle sensor 204. And the rotation amount of the sprocket 1 per predetermined time Δt determined based on the rotation signal POS output from the crank angle sensor 203 is selected, and the final angle change amount ΔASP (predetermined time of the sprocket 1) is selected. (Rotation amount per Δt).

The motor rotation angle detector 509 receives an output signal from the motor rotation angle sensor 210.
The motor rotation angle detection unit 509 performs an output signal detection process of the motor rotation angle sensor 210 by an interrupt process based on an input of the output signal of the motor rotation angle sensor 210. For example, when the motor rotation angle sensor 210 indicates the motor rotation angle by the duty ratio% of the output pulse signal, the motor rotation angle detection unit 509 measures the duty ratio of the output signal of the motor rotation angle sensor 210.

As the motor rotation angle sensor 210, a known sensor such as an encoder, a Hall IC, or a resolver can be employed as appropriate, and the motor rotation angle sensor 210 is not limited to a sensor that changes the duty ratio of the output pulse signal according to the rotation angle.
The motor rotation angle change amount calculation unit 510 performs a detection process result (previous detection output) by the motor rotation angle detection unit 509 at the time of the previous time (before the predetermined time Δt) and the current time by interruption processing every predetermined time Δt. As the difference from the detection processing result (current detection output) by the motor rotation angle detection unit 509 at the time of, the amount of change in the detection result per predetermined time Δt is calculated.

For example, when the motor rotation angle sensor 210 indicates the motor rotation angle by the duty ratio of the output pulse signal, the motor rotation angle change amount calculation unit 510 calculates the change amount (% / Δt) of the duty ratio per predetermined time Δt. To do.
Each time the motor rotation angle change amount calculation unit 510 calculates the change amount, the unit conversion unit 511 calculates the change amount as the angle change amount ΔAM (deg) per predetermined time Δt of the motor shaft 13, in other words, the motor shaft. 13 is converted into a rotation amount per predetermined time Δt.

The deviation calculation unit 512 includes the angle change amount ΔAM (deg) per predetermined time Δt of the motor shaft 13 calculated by the unit conversion unit 511 and the angle change amount of the sprocket 1 per predetermined time Δt output from the selection unit 508. ΔASP (deg) is input.
Then, the deviation calculation unit 512 has a deviation (difference) ΔA (ΔA = ΔAM−ΔASP) between the angle change amount ΔAM (deg) and the angle change amount ΔASP, that is, the rotation amount of the motor shaft 13 per predetermined time Δt, A deviation (difference) from the amount of rotation per predetermined time Δt of the sprocket 1 is calculated.

In the variable valve timing mechanism 114, when the motor shaft 13 rotates at the same rotational speed as the sprocket 1, the relative rotational phase angle (valve timing) of the intake camshaft 115a with respect to the crankshaft 109 does not change.
On the other hand, when the rotation speed of the motor 12 is controlled so that the rotation speed of the motor shaft 13 is higher than the rotation speed of the sprocket 1, in other words, the rotation amount per predetermined time Δt of the motor shaft 13 is calculated per predetermined time Δt of the sprocket 1. When the rotation amount is larger than the rotation amount, the relative rotation phase angle (valve timing) of the intake camshaft 115a with respect to the crankshaft 109 changes to the retard side.

Conversely, if the rotational speed of the motor shaft 13 is made slower than the rotational speed of the sprocket 1 by controlling the rotational speed of the motor 12, in other words, the rotational amount of the motor shaft 13 per predetermined time Δt is set to the predetermined time Δt of the sprocket 1. If the rotation amount is smaller than the winning rotation amount, the relative rotation phase angle (valve timing) of the intake camshaft 115a with respect to the crankshaft 109 changes to the advance side.
That is, the variable valve timing mechanism 114 changes the valve timing (actual relative rotational phase angle RA) in the advance direction or the retard direction according to the difference between the rotation amount of the motor shaft 13 and the rotation amount of the sprocket 1.

Therefore, the conversion unit 513 uses the angle change amount deviation ΔA (difference between the rotation amount per predetermined time Δt of the motor shaft 13 and the rotation amount per predetermined time Δt of the sprocket 1) calculated by the deviation calculation unit 512 as a reduction gear. 8 is converted into a change amount ΔRA (signed crank angle data) of the actual relative rotational phase angle RA per predetermined time Δt.
If the forward rotation direction of the internal combustion engine 101 and the advance direction of the valve timing are expressed as plus, the change amount ΔRA is a negative value (a value in the retard direction) when the angular change amount deviation ΔA is positive. The conversion unit 513 performs a process of multiplying “−1” in order to reverse the sign of the angle variation deviation ΔA, a correction process using the reduction ratio G of the speed reducer 8, and a unit conversion. Process.

  Then, the integration processing unit 514 uses the actual relative rotation phase angle RA1 updated every time the rotation angle signal CAM is generated by the rotation phase calculation unit 501 as an initial value, and outputs the actual value per predetermined time Δt output from the conversion unit 513. The change amount ΔRA of the relative rotational phase angle RA is integrated to calculate the final actual relative rotational phase angle RA (RA = RA1 + ∫ΔRA). In other words, the integration processing unit 514 calibrates the detected value of the actual relative rotational phase angle RA based on the integrated value of the change amount ΔRA based on the actual relative rotational phase angle RA1 every time the rotational angle signal CAM is generated.

  Thereby, the actual relative rotation phase angle RA1 is updated every time the rotation angle signal CAM is generated, whereas the actual relative rotation phase angle RA output from the integration processing unit 514 is updated every predetermined time Δt. Value. In other words, the change of the rotation phase while the actual relative rotation phase angle RA1 detected based on the rotation angle signal CAM and the rotation signal POS is updated is expressed as the rotation amount of the motor shaft 13 per predetermined time Δt and the sprocket 1. By detecting based on the difference from the rotation amount per predetermined time Δt, the update period of the actual relative rotation phase angle RA is made shorter than the generation period of the rotation angle signal CAM.

  The feedback control unit 515 is executed by interruption processing every predetermined time Δt or every time Δtc (for example, 10 ms) longer than the predetermined time Δt, and the latest value of the actual relative rotational phase angle RA output from the integration processing unit 514 and the illustration are omitted. The target relative rotation phase angle TA calculated by the calculated processing unit is read, and the operation amount of the variable valve timing mechanism 114 (the rotation control operation of the motor 12 is adjusted so that the actual relative rotation phase angle RA approaches the target relative rotation phase angle TA). (Quantity) is calculated and output.

  As described above, the change in the rotation phase while the actual relative rotation phase angle RA1 detected based on the rotation angle signal CAM and the rotation signal POS is updated is expressed as the rotation amount of the motor shaft 13 per predetermined time Δt and the sprocket. If the detection is based on the difference between the rotation amount per predetermined time Δt of 1 and the update period of the actual relative rotation phase angle RA used for the operation amount of the variable valve timing mechanism 114 is sufficiently high Since the actual relative rotational phase angle RA is converged to the target relative rotational phase angle TA with a high response, the occurrence of overshoot can be suppressed.

Here, when some abnormality (failure) occurs in the motor rotation angle sensor 210 and the change amount ΔRA cannot be calculated, the integration processing unit 514 stops the update processing of the actual relative rotation phase angle RA every predetermined time Δt. Each time the rotation angle signal CAM is generated, the data of the actual relative rotation phase angle RA1 output from the rotation phase calculation unit 501 is output as it is as the final actual relative rotation phase angle RA.
In this case, although the convergence to the target relative rotational phase angle TA is reduced, feedback control for bringing the actual relative rotational phase angle RA closer to the target relative rotational phase angle TA can be continued, and the valve timing of the intake valve 105 is set to the internal combustion engine. Control can be performed at an appropriate timing according to the operating state of the engine 101.
The integration processing unit 514 receives a flag indicating the result of failure diagnosis (presence / absence of failure) of the sensors 203, 204, and 210 used for detecting the rotational phase.

When the change amount ΔRA cannot be calculated due to an abnormality of the motor rotation angle sensor 210, in other words, when the update period of the actual relative rotation phase angle RA becomes longer than the predetermined time Δt, the normal state ( The gain of feedback control can be reduced compared to when the update cycle is a predetermined time Δt, and the occurrence of overshoot can be suppressed.
Also, if any abnormality occurs in either the crank angle sensor 203 or the cam angle sensor 204, the actual relative rotational phase angle RA1 cannot be calculated in the rotational phase calculation unit 501, but in this case, the integration processing unit 514 Stops the calibration process of the actual relative rotation phase angle RA every time the rotation angle signal CAM is generated, while continuing to update the actual relative rotation phase angle RA based on the change amount ΔRA.

That is, if any abnormality occurs in either the crank angle sensor 203 or the cam angle sensor 204, the control device 201 calculates the change amount ΔRA from the output of the normal side sensor and the output of the motor rotation angle sensor 210. Then, the actual relative rotational phase angle RA is updated every predetermined time Δt.
That is, the control device 201 detects the rotation phase based on the outputs of the two normal sensors when any one of the crank angle sensor 203, the cam angle sensor 204, and the motor rotation angle sensor 210 is abnormal. Then, the feedback control of the variable valve timing mechanism 114 is continued.

  As described above, if the selection unit 508 selects the larger one of the rotation amount of the sprocket 1 based on the crank angle signal POS and the rotation amount of the sprocket 1 based on the cam angle signal CAM, the crank angle sensor 203 is selected. When the abnormality occurs in either one of the cam angle sensor 204 and the cam angle sensor 204, it is possible to prevent the rotational phase from being erroneously detected to the retard side from the actual state and the valve timing from being excessively advanced from the target.

That is, when the angle change amount ΔASP of the sprocket 1 is detected to be smaller than the actual value, the actual relative rotational phase angle RA is detected on the more retarded side than the actual, but the selection unit 508 performs two rotations. If the larger one of the quantities is selected, it is possible to suppress the angular change amount ΔASP of the sprocket 1 from being detected to a value smaller than the actual value, so that the actual relative rotational phase angle RA is retarded from the actual value. Can be prevented from being detected.
Since the variable valve timing mechanism 114 controls the valve timing of the intake valve 105, when the valve timing is controlled to be advanced from the target, the opening timing IVO of the intake valve 105 is earlier than the target. Interference with the piston 108 may occur.

On the other hand, if the selection unit 508 selects the larger one of the two input rotation amount data, the change amount ΔRA can be prevented from being erroneously detected on the retard side more than the actual amount, and thus The occurrence of piston interference due to the excessive advance angle of the valve timing of the intake valve 105 can be suppressed.
The diagnosis of the presence / absence of abnormality of the crank angle sensor 203, the cam angle sensor 204, and the motor rotation angle sensor 210 is performed by a known failure diagnosis technique such as determination of consistency of detection results between sensors and detection of a pulse period of each sensor. Is appropriately used.

  In the example shown in FIG. 5, the selection unit 508 selects the larger one of the angle change amounts ΔASP1 and ΔASP2, but, for example, even if the variable valve timing mechanism 114 is controlled to the most advanced angle side, There is a possibility that the intake air amount of the internal combustion engine 101 is insufficient because the interference with the piston 108 does not occur and the closing timing IVC of the intake lube 105 is delayed after the bottom dead center BDC by being controlled to the most retarded angle side. In this case, the selection unit 508 can select a smaller one of the angle change amounts ΔASP1 and ΔASP2.

If the selection unit 508 selects the smaller one of the angle change amounts ΔASP1 and ΔASP2, it is possible to prevent the change amount ΔRA from being erroneously detected on the advance side, so that the valve timing of the intake valve 105 is excessive. It can suppress being retarded.
Even when the selection unit 508 selects the smaller one of the angle change amounts ΔASP1 and ΔASP2, a disconnection or the like occurs in either the crank angle sensor 203 or the cam angle sensor 204, and one of the angle change amounts ΔASP1 and ΔASP2 occurs. When one is calculated to be zero, the change amount ΔRA can be calculated based on the normal side angle change amount ΔASP.

  Also, as shown in FIGS. 6 and 7, the rotation amount of the sprocket 1 (angle change amount ΔASP2) based on the crank angle signal POS and the rotation amount of the sprocket 1 based on the cam angle signal CAM (angle change amount ΔASP1) are large. One of the rotation amount of the sprocket 1 based on the crank angle signal POS (angle change amount ΔASP2) and the rotation amount of the sprocket 1 based on the cam angle signal CAM (angle change amount ΔASP1) is used as a crank angle sensor. A selection can be made based on the result of failure diagnosis 203 and the result of failure diagnosis of the cam angle sensor 204, and output to the deviation calculation unit 512.

In FIG. 6, the selection unit 508 selects the larger one of the rotation amount (angle change amount ΔASP2) of the sprocket 1 based on the crank angle signal POS and the rotation amount (angle change amount ΔASP1) of the sprocket 1 based on the cam angle signal CAM. And output to the output switching unit 520.
The output switching unit 520 outputs the output of the selection unit 508, the rotation amount of the sprocket 1 based on the crank angle signal POS (angle change amount ΔASP2), and the rotation amount of the sprocket 1 based on the cam angle signal CAM (angle change amount ΔASP1). And a selection command signal SW based on the result of failure diagnosis of the crank angle sensor 203 and the result of failure diagnosis of the cam angle sensor 204 are input, and one of the three input signals is input based on the selection command signal SW. Select and output to deviation calculator 512.

As shown in FIG. 7, the selection command signal SW is switched to three types of signals according to the result of failure diagnosis of the crank angle sensor 203 and the result of failure diagnosis of the cam angle sensor 204.
Specifically, before the occurrence of failure of the crank angle sensor 203 and the cam angle sensor 204 is determined, the selection command signal SW is set as a command for selecting the output of the selection unit 508, and the failure of the crank angle sensor 203 is determined. When confirmed, the selection command signal SW is set as a command for selecting the rotation amount (angle change amount ΔASP1) of the sprocket 1 based on the cam angle signal CAM. When the failure of the cam angle sensor 204 is confirmed, the selection command signal SW is It is set as a command for selecting the rotation amount (angle change amount ΔASP2) of the sprocket 1 based on the crank angle signal POS.

That is, in the state where the failure occurrence is not diagnosed for the crank angle sensor 203 and the cam angle sensor 204, the larger one of the rotation amount of the sprocket 1 based on the crank angle signal POS and the rotation amount of the sprocket 1 based on the cam angle signal CAM. When the selection is made and the occurrence of a failure is diagnosed for either the crank angle sensor 203 or the cam angle sensor 204, the rotation amount of the sprocket 1 is selected based on the sensor output on the normal side.
As a result, when either the crank angle sensor 203 or the cam angle sensor 204 fails, the rotation amount of the sprocket 1 based on the output of the normal sensor can be output stably, and the control reliability can be improved. Can be improved.

  The selection unit 508 also determines the rotation amount of the sprocket 1 based on the crank angle signal POS when both sensors are normal based on the failure diagnosis result of the crank angle sensor 203 and the failure diagnosis result of the cam angle sensor 204. When the occurrence of a failure of the cam angle sensor 204 is diagnosed, the detection value of the rotation amount of the sprocket 1 based on the crank angle signal POS is output, and the occurrence of a failure of the crank angle sensor 203 is diagnosed. In addition, a detection value of the rotation amount of the sprocket 1 based on the cam angle signal CAM can be output.

Further, in the internal combustion engine 101 including the exhaust side variable valve timing mechanism that makes the phase of the valve operating angle of the exhaust valve 110 variable and the exhaust side cam angle sensor 204E that outputs the rotation angle signal CAM of the exhaust camshaft, FIG. As shown in FIG. 8, the angle change amount ΔASP1 is calculated based on the output of the exhaust side cam angle sensor 204E, and the angle change amount ΔASP1 is output to the selection unit 508 or the like.
That is, in FIG. 8, the CAM cycle calculation unit 502E calculates the CAM cycle TREFE (ms), which is the generation cycle of the rotation angle signal CAME, by an interrupt process based on the input of the rotation angle signal CAME output from the exhaust cam angle sensor 204E. The rotation amount calculation unit 504E measures the latest CAM cycle TREFE calculated by the CAM cycle calculation unit 502E by interruption processing every predetermined time Δt, and reads the CAM cycle TREFE from the read CAM cycle TREFE per predetermined time Δt. An angle change amount ΔASP1 (deg) is calculated.

When the configuration of FIG. 8 is adopted, when a failure of the intake side cam angle sensor 204 is confirmed (diagnosed), the phase change of the valve operating angle of the exhaust valve 110 by the exhaust side variable valve timing mechanism is stopped, and the phase Can be fixed to a preset default position (for example, the most retarded angle position) or a phase at the time of diagnosis confirmation.
Thereby, the calculation accuracy of the angle change amount ΔASP1 based on the output of the exhaust side cam angle sensor 204E is improved, and the control accuracy of the variable valve timing mechanism 114 when the intake side cam angle sensor 204 is out of order is improved.
In the case of the above configuration, the operation of the exhaust side variable valve timing mechanism stops due to the failure of the intake side cam angle sensor 204, but rather than the case where the operation of the intake side variable valve timing mechanism stops. The influence on the drivability of the internal combustion engine 101 is small.

Further, the integration processing unit 514 calibrates the detection value of the actual relative rotation phase angle RA based on the integration value of the change amount ΔRA based on the actual relative rotation phase angle RA1 every time the rotation angle signal CAM is generated. When the change amount ΔASP1> the angle change amount ΔASP2 and the selection unit 508 selects and outputs the angle change amount ΔASP1, the calibration process of the actual relative rotation phase angle RA based on the actual relative rotation phase angle RA1 is stopped. it can.
That is, when the angle change amount ΔASP1> the angle change amount ΔASP2, it is considered that a failure has occurred in the crank angle sensor 203, and the accuracy of the actual relative rotation phase angle RA1 is reduced, so the actual relative rotation phase angle RA1. By stopping the calibration process of the actual relative rotational phase angle RA based on the above, it is possible to suppress the actual relative rotational phase angle RA from being erroneously calibrated.

In the functional block diagram of FIG. 5, the CAM cycle calculation unit 502 that measures the CAM cycle TREF (ms), which is the generation cycle of the rotation angle signal CAM output from the cam angle sensor 204, and the CAM cycle calculation unit 502 have calculated. The rotation amount calculation unit 504 calculates an angle change amount ΔASP1 (deg) based on the CAM cycle TREF. Instead of the CAM cycle calculation unit 502 and the rotation amount calculation unit 504, as shown in FIG. A count unit 521 and a count change amount calculation unit 522 can be provided.
The CAM count unit 521 increments the counter value every time the cam angle sensor 204 outputs the rotation angle signal CAM, and the count change amount calculation unit 522 determines the counter value read this time (before the predetermined time Δt) and the current value. A difference from the read counter value is calculated as a change amount of the counter per predetermined time Δt, and this change amount is converted into an angle change amount ΔASP1.

In the functional block diagram of FIG. 5, the POS count unit 503 that increments the counter every time the rotation angle signal POS output from the crank angle sensor 203 is input, and the count value NPOS updated by the POS count unit 503 are read. 10 includes a count change amount calculation unit 505 that calculates the change amount ΔNPOS of the count value NPOS per predetermined time Δt. Instead of the POS count unit 503 and the count change amount calculation unit 505, as shown in FIG. , A POS cycle calculation unit 523 and a rotation amount calculation unit 524 can be provided.
The POS cycle calculation unit 523 measures the generation cycle (ms) of the rotation angle signal POS output from the crank angle sensor 203, and the rotation amount calculation unit 524 uses the POS cycle TPOS calculated by the POS cycle calculation unit 523 as the change amount ΔNPOS. (Or angle change amount ΔASP2).

  When the variable valve timing mechanism 114 is configured to advance the phase by rotating the motor shaft in the direction opposite to the engine rotation direction, the variable valve timing mechanism 114 is operated according to the functional block diagram of FIG. However, when the variable valve timing mechanism 114 is configured to advance the phase by rotating the motor shaft in the same direction as the engine rotation direction, the variable valve timing mechanism 114 is operated according to the functional block diagram shown in FIG. be able to.

The functional block diagram of FIG. 11 is different from the functional block diagram of FIG. 5 in the configuration of the selection unit 508 and the conversion unit 513.
Specifically, the selection unit 508S shown in the functional block diagram of FIG. 11 is the rotation that the cam angle sensor 204 outputs, which is the smaller of the angle change amount ΔASP1 (deg) and the angle change amount ΔASP2 (deg). The smaller one of the rotation amount of the sprocket 1 per predetermined time Δt determined based on the signal CAM and the rotation amount of the sprocket 1 per predetermined time Δt determined based on the rotation signal POS output from the crank angle sensor 203 is selected. Is output as a typical angle change amount ΔASP (amount of rotation of the sprocket 1 per predetermined time Δt).
In the conversion unit 513S shown in the functional block diagram of FIG. 11, since it is not necessary to reverse the sign of the angle change amount deviation ΔA, the angle change amount deviation ΔA is multiplied by “1” to reduce the reduction ratio of the reducer 8 About the correction process and unit conversion process by G, the process similar to the case of FIG. 5 is performed.

Further, when a failure of the cam angle sensor 204 or the crank angle sensor 203 is diagnosed (determined), the variable valve timing mechanism 114 is positioned by a default position (for example, a stopper) in order to improve the subsequent phase detection accuracy. (The most retarded angle position or the most advanced angle position), and the accumulated value of the change amount ΔRA in the accumulation processing unit 514 can be cleared to an initial value (for example, zero).
The time chart of FIG. 12 shows an example of the default control and the integrated value clearing process based on the above-described failure diagnosis.

In FIG. 12, the variable valve timing mechanism 114 is controlled based on the output of the accumulating unit 514 during the period until the time t1 is reached (until the occurrence of failure), and the cam angle sensor 204 or the crank at the time t1. When the failure of the angle sensor 203 is diagnosed (determined), control (default control) toward the default position of the variable valve timing mechanism 114 is started.
Then, when it is detected that the variable valve timing mechanism 114 has reached the default position at time t2, the integrated value of the change amount ΔRA is updated to the initial value, and then the actual phase angle is brought closer to the target phase angle TA. (Normal control) is resumed.

Although the contents of the present invention have been specifically described above with reference to the preferred embodiments, it is obvious that those skilled in the art can take various modifications based on the basic technical idea and teachings of the present invention. is there.
For example, when the abnormality occurs in two or three of the crank angle sensor 203, the cam angle sensor 204, and the motor rotation angle sensor 210, the control device 201 cannot detect the actual rotation phase. The motor 12 can be controlled so that the rotation phase by the timing mechanism 114 returns to the initial position (the most retarded angle position or the most advanced angle position).

  Also in the variable valve timing mechanism that makes the valve timing of the exhaust valve 110 variable, any one of the crank angle sensor 203, the cam angle sensor that outputs the exhaust camshaft rotation angle signal CAM, and the motor rotation angle sensor 210. When an abnormality occurs, the rotational phase of the exhaust camshaft relative to the crankshaft 109 can be detected based on the outputs of two normal sensors.

  In addition, when either the crank angle sensor 203 or the cam angle sensor 204 fails and the actual relative rotational phase angle RA1 cannot be detected, a failure occurs instead of the target rotational phase in the normal state of the sensor. The target valve phase in the state is set, and the variable valve timing mechanism 114 (motor 12) can be controlled so that the actual rotation phase updated based on the change amount ΔRA approaches the target value for failure.

  Further, when an abnormality occurs in one of the crank angle sensor 203, the cam angle sensor 204, and the motor rotation angle sensor 210, the variable range of the target rotation phase is limited to be narrower than that in the normal state, so that the over advance angle Alternatively, the excessive retardation can be suppressed.

  In addition to the variable valve timing mechanism, a variable operating angle mechanism that varies the operating angle of the intake valve or the exhaust valve can be provided. In the internal combustion engine 101 including the variable valve timing mechanism and the variable operating angle mechanism, when an abnormality occurs in one of the crank angle sensor 203, the cam angle sensor 204, and the motor rotation angle sensor 210, the variable operating angle mechanism It is possible to limit the change in the increase in the operating angle caused by the pressure difference from the normal state, and to suppress the occurrence of piston interference.

  Further, in the configuration in which the selection unit 508 selects the larger one of the two rotation amounts, when one rotation amount is a rotation amount larger than the upper limit value, the selection unit 508 is configured to select the smaller one on the contrary, When an abnormally high amount of rotation is calculated due to an abnormality in the sensor signal processing circuit or the like, it is possible to suppress erroneous selection of the amount of rotation.

  DESCRIPTION OF SYMBOLS 12 ... Motor, 101 ... Internal combustion engine, 105 ... Intake valve, 109 ... Crankshaft, 114 ... Variable valve timing mechanism, 115a ... Intake camshaft, 201 ... Control device, 203 ... Crank angle sensor, 204 ... Cam angle sensor, 210 ... Motor rotation angle sensor

Claims (4)

A variable valve timing mechanism that changes the rotational phase of the camshaft relative to the crankshaft by adjusting the rotational speed of the motor, a crank angle sensor that outputs a crank angle signal at a predetermined angular position of the crankshaft, and a predetermined angular position of the camshaft A control device applied to an internal combustion engine including a cam angle sensor that outputs a cam angle signal and a motor rotation angle sensor that detects a rotation angle of a rotation shaft of the motor,
The larger of the rotation amount of the cam sprocket calculated based on the crank angle signal and the rotation amount of the cam sprocket calculated based on the cam angle signal is selected, and the selected rotation amount of the cam sprocket and the motor rotation are selected. Obtaining the amount of change in the rotational phase from the amount of rotation of the rotating shaft of the motor calculated based on the output of the angle sensor,
When one of the crank angle sensor and the cam angle sensor is abnormal, the change amount of the rotation phase is obtained based on the output of the other normal sensor and the output of the motor rotation angle sensor.
Control device for internal combustion engine. A variable valve timing mechanism that changes the rotational phase of the camshaft relative to the crankshaft by adjusting the rotational speed of the motor, a crank angle sensor that outputs a crank angle signal at a predetermined angular position of the crankshaft, and a predetermined angular position of the camshaft A control device applied to an internal combustion engine including a cam angle sensor that outputs a cam angle signal and a motor rotation angle sensor that detects a rotation angle of a rotation shaft of the motor,
The larger of the rotation amount of the cam sprocket calculated based on the crank angle signal and the rotation amount of the cam sprocket calculated based on the cam angle signal is selected, and the selected rotation amount of the cam sprocket and the motor rotation are selected. Obtaining the amount of change in the rotational phase from the amount of rotation of the rotating shaft of the motor calculated based on the output of the angle sensor,
Each time the cam angle signal is output, the rotational phase is detected based on the cam angle signal and the crank angle signal,
The rotation phase detected each time the cam angle signal is output is set as an initial value, and the detection value of the rotation phase is updated based on the integrated value of the change amount,
Wherein when either one of the crank angle sensor and the cam angle sensor is abnormal, the together with the detecting the amount of change in the rotational phase on the basis of the other of the outputs of the normal sensor and the output of the motor rotation angle sensor Stop updating the initial value,
Control device for internal combustion engine . The control device for an internal combustion engine according to claim 2, wherein when the motor rotation angle sensor is abnormal, updating of the detected value of the rotation phase based on the integrated value of the change amount is stopped . A variable valve timing mechanism that changes the rotational phase of the camshaft relative to the crankshaft by adjusting the rotational speed of the motor, a crank angle sensor that outputs a crank angle signal at a predetermined angular position of the crankshaft, and a predetermined angular position of the camshaft A control device applied to an internal combustion engine including a cam angle sensor that outputs a cam angle signal and a motor rotation angle sensor that detects a rotation angle of a rotation shaft of the motor,
The larger of the rotation amount of the cam sprocket calculated based on the crank angle signal and the rotation amount of the cam sprocket calculated based on the cam angle signal is selected, and the selected rotation amount of the cam sprocket and the motor rotation are selected. A control device for an internal combustion engine, which obtains a change amount of the rotation phase from a rotation amount of a rotation shaft of the motor calculated based on an output of an angle sensor .